DISEASES AND ENEMIES 245 



fertile. In some countries lime at the rate of 10 

 kilograms per 100 square feet is applied with success. 



Canker. This is probably the most widely spread 

 cocoa disease. It has been observed in America (the 

 Antilles, Surinam), in Africa (Kamerun), and Asia 

 (Ceylon, Java, Samoa). 



When the cocoa tree is attacked by canker, moist 

 spots appear on the bark of the stem and also (but not 

 to the same extent) on the main branches. When the 

 canker has just started and the spots are small, they 

 are easily overlooked ; but when they become larger 

 and older, they take on a dark colour, the fluid flows 

 out more freely, and sometimes a gummy exudation 

 is also to be seen. When the spots dry up, a more or 

 less brownish tinge appears. If the outer layer of the 

 bark be cut away, the disease is much more conspicuous 

 (Fig. 80), and the affected parts of the bark appear as 

 light, claret-coloured areas. Later on the claret colour 

 grows darker. 



Though it principally attacks the bark, the fungus 

 is not always confined to this part. Not infrequently 

 it penetrates into the wood, which assumes a brownish 

 or reddish colour, and this dark discoloration is some- 

 times continued in characteristic narrow stripes far 

 under the healthy bark or into the wood. 



Trees which are severely attacked are sometimes 

 killed, when the dead tree may be seen still bearing a 

 good number of dead leaves. Generally, however, the 

 decay is slower, the foliage becomes gradually thinner, 

 and it may be a long time, sometimes several months, 

 before the tree actually dies. Very often the tree 

 recovers from an attack, especially when the season 

 becomes dry, and the infection remains confined to 

 one or more larger or smaller spots which dry up and 

 become completely separated from the healthy parts by 

 a layer of wound-cork. In this case it is easily loosened 

 and removed as a whole by means of a knife or some 

 other instrument. 



In the discoloured parts of the bark and wood the 



